use std::env;
use std::fs;

mod language;
mod state;
mod detect_filetype;
mod highlighter;
mod keywords;
mod specials;
mod col;
mod ccat_markdown;

use crate::state::State;
use crate::detect_filetype::detect_language;
use crate::highlighter::{highlight_line, print_binary_file};
use crate::col::HighlightConfig;
use crate::language::Language;
use crate::ccat_markdown::{md_html_main, md_ansi_main};
use crate::specials::{print_hex_file, log_highlight_line, to_c_array};

const INFO_TEXT: &str = r#"
Syntax: ccat <datei> [Optionen]
@VERSION 2.9.4 Rust

c <filename> <options ...>

Optionen:
    n   = Zeilennummern anzeigen
    b   = Binärdatei als Hex-Dump ausgeben
    r   = Remove all ANSI (save mode)
    h   = print as HTML Source
    a   = print file as C Hexadezimal Array
    x   = print as hex dump

    -s, --stop <nr> letzte auszugebende Zeile
"#;

fn read_file_with_hex_fallback(path: &str, output: &mut String) {
    output.clear();
    let bytes = match fs::read(path) {
        Ok(data) => data,
        Err(e) => {
            eprintln!("Fehler beim Lesen von '{}': {}", path, e);
            std::process::exit(1);
        }
    };
    output.reserve(bytes.len() * 2);
    let mut i = 0;
    while i < bytes.len() {
        if let Some((ch, len)) = decode_next_utf8_char(&bytes[i..]) {
            output.push(ch);
            i += len;
        } else {
            output.push_str(&format!(" 0x{:02X}", bytes[i]));
            i += 1;
        }
    }
}

fn decode_next_utf8_char(slice: &[u8]) -> Option<(char, usize)> {
    if slice.is_empty() {
        return None;
    }
    let byte = slice[0];
    if matches!(byte, b'\n' | b'\r' | b'\t') {
        return Some((byte as char, 1));
    }
    if (32..=126).contains(&byte) {
        return Some((byte as char, 1));
    }
    if byte >= 128 {
        for len in 2..=4 {
            if len > slice.len() {
                break;
            }
            if let Ok(s) = std::str::from_utf8(&slice[..len]) {
                if let Some(ch) = s.chars().next() {
                    if ch.len_utf8() == len {
                        if !ch.is_control() {
                            return Some((ch, len));
                        }
                    }
                }
            }
        }
    }
    None
}

fn remove_ansi_escapes(input: &str, output: &mut String) {
    output.clear();
    let bytes = input.as_bytes();
    let mut i = 0;
    while i < bytes.len() {
        if bytes[i] == 0x1B {
            if i + 1 < bytes.len() && bytes[i + 1] == b'[' {
                i += 2;
                while i < bytes.len() {
                    let b = bytes[i];
                    i += 1;
                    if (b'A'..=b'Z').contains(&b) || (b'a'..=b'z').contains(&b) || (b'@'..=b'~').contains(&b) {
                        break;
                    }
                }
                continue;
            }
        }
        output.push(bytes[i] as char);
        i += 1;
    }
}

fn get_int_by_string(s: String) -> u64
{
    let num: u64 = s.parse().unwrap();
    return num;
}

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() == 1 {
        print!("{}", INFO_TEXT);
        return;
    }
    let mut state = State::new();
    if args.len() >= 3 {
        for ch in args[2].chars() {
            match ch {
                'n' => state.flag_nr = true,
                'b' => state.print_binary = true,
                'r' => state.remove_all_ansi = true,
                'h' => state.html_color = true,
                'x' => state.hex = true,
                'a' => state.to_c_array = true,
                _ => {}
            }
        }
        if args[2] == "-s" || args[2] == "--stop" {
            state.stop_at_line = get_int_by_string(args[3].clone());
        } else {
            state.stop_at_line = 0xFFFFFFFFFFFFF000;
        }
    }
    let filename = &args[1];
    let lang = detect_language(filename);
    let mut source = String::new();
    let mut source_len = 0x1000;
    if !state.print_binary {
        read_file_with_hex_fallback(filename, &mut source);
        source_len = source.len();
    }
    let mut output = String::with_capacity(source_len * 2);
    let mut jump: bool = false;
    let config = if state.html_color {
        HighlightConfig::html_colors()
    } else {
        HighlightConfig::default()
    };
    if state.hex {
        print_hex_file(filename, &mut state, &config);
        jump = true;
    }
    if lang == Language::LogFile {
        for line in source.lines() {
            log_highlight_line(line, &mut state, &config);
        }
        jump = true;
    }
    if state.to_c_array {
        to_c_array(filename, &config);
        jump = true;
    }
    if state.print_binary {
        print_binary_file(filename, &mut output, &mut state, &config);
        jump = true;
    }
    if state.remove_all_ansi {
        remove_ansi_escapes(&source, &mut output);
        jump = true;
    }
    if !jump {
        if lang == Language::Markdown {
            if state.html_color {
                md_html_main(&source, &mut output);
            } else {
                md_ansi_main(&source, &mut output);
            }
        } else {
            for line in source.lines() {
                let stop_flag: bool = highlight_line(line, lang, &config, &mut output, &mut state);
                if stop_flag {
                    break;
                }
            }
        }
    }
    println!("{}", output);
}


#[cfg(test)]
mod tests {
    use super::*;

    fn test_with_file(filename: &str, content: &[u8], expected: &str) {
        let filepath = format!("/tmp/{}", filename);
        fs::write(&filepath, content).unwrap_or_else(|e| {
            panic!("Konnte Testdatei nicht erstellen {}: {}", filepath, e);
        });
        let mut result = String::new();
        read_file_with_hex_fallback(&filepath, &mut result);
        assert_eq!(result, expected, "Testdatei {} fehlgeschlagen", filename);
        let _ = fs::remove_file(&filepath);
    }

    #[test]
    fn test_unicode_and_hex() {
        test_with_file(
            "rust_test_unicode.bin",
            b"Hello \xC3\xA4\xC3\xB6\xC3\xBC\xC3\x9F \xE2\x82\xAC \xF0\x9F\x9A\x80 World!\n\x00\x07\xFF",
            "Hello äöüß € 🚀 World!\n 0x00 0x07 0xFF",
        );
    }

    #[test]
    fn test_invalid_utf8_sequences() {
        test_with_file(
            "rust_test_invalid.bin",
            b"Valid text \xFF\xFE\xFD invalid again \xC3( broken \xE2\x82\xFF end",
            "Valid text  0xFF 0xFE 0xFD invalid again  0xC3( broken  0xE2 0x82 0xFF end",
        );
    }

    #[test]
    fn test_only_printable_text() {
        test_with_file(
            "rust_test_text.txt",
            b"Hello World!\nThis is a test.\nLine 3 with umlauts: \xC3\xA4\xC3\xB6\xC3\xBC\xC3\x9F",
            "Hello World!\nThis is a test.\nLine 3 with umlauts: äöüß",
        );
    }

    #[test]
    fn test_control_characters() {
        test_with_file(
            "rust_test_control.bin",
            b"Line1\nLine2\r\nTab\t\x00\x01\x02\x1F\x7F\xFF",
            "Line1\nLine2\r\nTab\t 0x00 0x01 0x02 0x1F 0x7F 0xFF",
        );
    }

    #[test]
    fn test_empty_file() {
        test_with_file("rust_test_empty.bin", b"", "");
    }
}